The NMR relaxation times, T1, T2 and T1p of a variety of malignant and non-malignant tissues of humans and small animals will be measured and histopathological studies will be carried out on the same tissues. The results will be compared and interpreted in terms of the potential use of NMR as a method of cancer diagnosis. In addition, the underlying physical basis of the observed phenomenon of longer NMR relaxation times associated with malignant tumors will be studied with the aim of delineating the mechanism of this effect and its possible relationships to cancer diagnosis and investigation.